A tandem type image forming apparatus as an electro-photographic type image forming apparatus is known in which are provided a plurality of photosensitive drums, a transfer belt positioned in confrontation therewith, a plurality of process cartridges for a plurality of colors such as for example, yellow, magenta, cyan and black, and a drawer unit configured to support the process cartridges.
In such a tandem type image forming apparatus, each process cartridge is provided with a drum-cleaning unit configured to remove waste toner remaining on each photosensitive drum associated with each process cartridge, and a waste toner container configured to accumulate the waste toner removed by the drum-cleaning unit.
Further, Japanese patent application publication No. 2010-102285 discloses such a tandem type image forming apparatus in which a belt cleaning unit and a waste toner container are provided in an internal space of a frame of the device. The belt cleaning unit is positioned below the transfer belt and is configured to remove waste toner remaining on the transfer belt. The waste toner container is configured to accumulate waste toner removed by the belt cleaning unit.